Irrigation districts and the national wildlife refuges have made calls.

The tribes exercised their right last year in the interest of fish they hold sacred, keeping water in streams running through their former reservation lands.

“I don't know if we are going to be regulating or not. It's too early to tell,” said Scott White, watermaster at the Klamath Falls office of the Oregon Water Resources Department office.

Flows into Upper Klamath Lake and the snow pack at Crater Lake are well below averages — 6 percent of normal at one observation point in the national park.

Irrigators in a district along the Oregon-California border have enough water now because of mid-May rain, but the heaviest demand comes as the crops emerge in June and face the heat of July.

“Everybody is pretty worried about what's going to happen later,” said Ron Fenster, watermaster of the Tulelake Irrigation District.

Wildlife such as birds using wetlands on the Pacific Flyway are likely to suffer. Acting Manager Greg Austin said the Lower Klamath National Wildlife Refuge hasn't had water deliveries since November, and it is expected to be dry by the end of July.

The forecast through August is expected to be warmer and drier than normal, said Ryan Sandler, a National Weather Service meteorologist.